This invention relates to multilayered material, especially containers having properties which are not obtainable in a single layered product.
Multilayered plastic containers are highly desirable whenever it is difficult to satisfy all of the requirements and specifications by using a single plastic.
For example, the low cost, easy formability, impact resistance and other desirable properties of polystyrene, polyvinyl chloride and polyolefins, especially polyethylene, would make them highly desirable containers for many commodities; however, for example, polyethylene does not have sufficient barrier or solvent resistance for many applications.
In instances of this kind, it has been attempted to provide a lined container, wherein the container wall is composed of more than one substance and thereby provide properties that no single plastic possesses.
However, heretofore the economical production of such containers was prohibitively difficult. In addition, certain combinations of properties presented considerable difficulties even in a composite container.
For example, it is highly desirable to obtain a plastic container having resistance to exposure to elevated temperatures, such as above 175.degree. F. and preferably above 220.degree. F., while at the same time having fluid barrier resistance, such as gas barrier resistance as resistance to the transmission of oxygen and carbon dioxide, or solvent resistance. In the production of composite containers of this type, however, it is known that when the container is exposed to elevated temperature conditions, as, for example, when filling with substances at such temperatures, the barrier material tends to melt, destroying the integrity and utility of the container.
Accordingly, it is a principal object of the present invention to provide a multilayered plastic, especially a hollow plastic container.
It is a particular object of the present invention to provide a plastic sheet material and container as aforesaid having resistance to elevated temperatures and barrier resistance.
It is an additional object of the present invention to provide a container as aforesaid wherein said container retains fluid barrier resistance upon repeated exposure to elevated temperatures.
It is a still further object of the present invention to provide a container as aforesaid which can be simply and conveniently prepared in accordance with the present invention.
Further objects and advantages of the present invention will appear hereinbelow.